TRANSCRIPT

Boy1: We're known as the tree house detectives.

Woman: Oh.

Boy1: We're trying to get some sleep, but the neighborhood dogs are keeping us up.

Boy2: We wanted to know how our ears work. That way we can figure out why the dogs keep barking.

Boy1: And how sound travels. If we knew how sound travels that might help us solve the problem.

Woman: I think I can help you out. Let's move into the other room.

Boy2: What is all this stuff?

Woman: This is equipment we use to test people's hearing.

Boy1: Can you tell us how our ears work?

Woman: Sure.

Woman VO: The outer ear collects and concentrates the sound energy. Then this is channeled down the ear canal and the eardrum vibrates and so do the small bones within the ear. Then the sounds go through the cochlea, the hair cells bend, and then the impulses are sent up the auditory nerve and into the brain where they are decoded.

Boy2: Are there sounds people can't hear?

Woman: Sure, if they are above a certain frequency. The human ear can hear frequencies between 20 and 20,000 vibrations a second.

Boy1: Frequencies. Hmmm. That might be a clue. Thanks for all your help.

Woman: Sure.

Boy2: Bye.

Woman. Bye and good luck.